Difference method for analysing infrared images in pigs with elevated body temperatures.

Infrared imaging proves to be a quick and simple method for measuring temperature distribution on the pig's head. The study showed that infrared imaging and analysis with a difference ROI (region of interest) method may be used for early detection of elevated body temperature in pigs (> 39.5°C). A high specificity of approx. 85% and a high sensitivity of 86% existed. The only prerequisite is that there are at least 2 anatomical regions which can be recognised as reproducible in the IR image. Noise suppression is guaranteed by averaging the temperature value within both of these ROI. The subsequent difference imaging extensively reduces the off-set error which varies in every thermal IR-image.